Origin and Distribution of Cr2, a Gene for Resistance to White Pine Blister Rust in Natural Populations of Western White Pine
Bibliographic record
Abstract
ABSTRACT The distribution and frequency of the Cr2 gene for resistance to white pine blister rust (Cronartium ribicola) in western white pine (Pinus monticola) was surveyed in natural populations of the host by inoculation of open-pollinated seedlings from 687 individual seed parents from throughout most of the species' range. Because Cr2 is dominant and results in a conspicuous hypersensitive reaction (HR) in pine needles, the phenotype can readily be detected in offspring of susceptible seed parents fertilized by unknown Cr2 donors in the ambient pollen cloud. Gametic frequencies of Cr2 were thus determined as the proportion of total challenged seedlings that were pollen receptors exhibiting the Cr2 phenotype. Zygotic frequencies, the proportion of seed parents with progeny that segregated in Mendelian ratios for the Cr2 phenotype to the total number of parents, were a complementary, though less precise, measure. Cr2 frequency was rare overall, ranging from 0.004 to 0.008 in the Sierra Nevada to about 0.001 in the central Cascade Range; it was undetectable further north in the Cascades, as well as in the Rocky Mountains and Coast Mountains of the United States and Canada. The diminishing frequency of Cr2 from the southern and central Sierra Nevada northward mirrors that of Cr1 in sugar pine (P. lambertiana) and points to this region as the origin of both genes. We rationalize that this coincidence may have resulted from protection that these genes may have conferred on both species to an endemic pine stem rust congeneric with C. ribicola (C. occidentale) in recent geologic epochs.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".